Heat exchangers

ABSTRACT

THIS INVENTION RELATES TO HEAT EXCHANGERS COMPRISING AT LEAST ONE MANIFOLD TUBE INTERCONNECTING A PLURALITY OF PASSAGE MEMBERS THROUGH WHICH A LIQUID CAN FLOW, WHEREIN THE MANIFOLD TUBE PASSES THROUGH APERTURES IN THE WALLS OF THE PASSAGE MEMBERS AND IS CONSTRUCTED TO ALLOW FOR LIQUID FLOW BETWEEN THE MANIFOLD TUBE AND THE PASSAGE MEMBERS. THE PASSAGE MEMBERS AND MANIFOLD TUBE ARE SECURED TOGETHER BY MEANS OF SURROUNDING MEMBERS AFFIXED TO BOTH THE MANIFOLD TUBE AND PASSAGE MEMBERS. THE INVENTION ALSO DISCLOSED FEATURES OF AN EXPANSION CONTAINER CONNECTED TO THE MANIFOLD.

Sept. 1971 P. R. SMITH ETAL 3,605,882

HEAT EXOHANGERS Filed June 9. 1969 5 Sheets-Sheet 1 2a 2 L 1a 2a Fig.1B Fig.1C

Sept. 20, 1971 P. R. SMITH ETAL 3,605,882

mm nxcnmemns Filed June 9, 1969 5 Sheets-Sheet 2 l. s{ Fig. I

Sept. 20, 1971 P. R. SMITH ETAL HEAT EXCHANGERS 5 Sheets-Sheet 5 Filed June 9, 1969 (lllllll P. R. SMITH EI'AL HEAT EXOHANGERS Sept. 20, 1971 5 Sheets-Sheet 6 Filed June 9, 1969 8 Shasta-Sheet I HEAT EXGHANGERS P. R. SMITH ETAL 0 A 1 g g .l 7 l f0 8 Z 2 2 2 2 4 3 3 I I H- 9 2 \\\\\\\\\\N 3 2 w u. Z f a n f /V 5 5 2 Sept. 20, 1971 Filed June 9, 1969 nited Stes Patent 6 3,605,882 Patented Sept. 20, 1971 3,605,882 HEAT EXCHANGERS Peter Roy Smith, Colin Raymond Bemrose, and Henry John Levington, Leamington Spa, England, assignors to Associated Engineering Limited, Leamington Spa, England Filed June 9, 1969, Ser. No. 831,404 Claims priority, application Great Britain, July 2, 1968, 31,589/68; Nov. 6, 1968, 52,686/68 Int. Cl. F28f 9/00 US. Cl. 165-173 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to heat exchangers comprising at least one manifold tube interconnecting a plurality of passage members through which a liquid can flow, wherein the manifold tube passes through apertures in the walls of the passage members and is constructed to allow for liquid flow between the manifold tube and the passage members. The passage members and manifold tube are secured together by means of surrounding members affixed to both the manifold tube and passage members. The invention also discloses features of an expansion container connected to the manifold.

The present invention relates to heat exchangers and more particularly to radiators for liquid cooled internal combustion engines.

The invention is particularly concerned with manifold type radiators for internal combustion engines, that is to say radiators of the kind incorporating one or more manifolds interconnecting a plurality of passage members for a liquid coolant. Generally the passage members are provided with, or in contact with, cooling surfaces such as fins for dissipating heat transferred to the passage members from the liquid passing therethrough.

From one aspect, the present invention provides a heat exchanger comprising at least one manifold interconnecting a plurality of passage members through which a liquid can flow wherein the passage members are provided with an aperture in their walls through which passes a manifold tube having at least a part of one or more apertures located opposite each passage member to allow for liquid flow between the manifold tube and that passage member, and wherein each passage member is secured to the or each manifold tube by means of surrounding members extending around the manifold tube and secured both to the external surface of said tube and to the adjacent wall of said passage member.

According to one form of the invention, the surrounding members may comprise a flanged collar or ferrule extending around the manifold tube on each side of a passage member. Alternatively, each surrounding member may be dimensioned to form a distance piece extending between successive passage members and be provided with side faces or flanges respectively secured to the adjacent passage members.

Advantageously, the surrounding members are bonded to the manifold tube and the passage members by means of an adhesive tube and where an adhesive is employed, each surrounding member may be provided with a recess on its inner surface which communicates with the outer surface of the member through one or more holes through which adhesive can be injected into the recess in order to bond the member to the manifold tube. Alternatively recesses may be provided in the manifold tube.

In yet another construction, the surrounding members, in the form of a distance piece, are secured to the manifold tube by indenting the member so that its inner wall projects into a depression formed on the manifold tube.

The depressions may either be preformed in the manifold tube or may be formed simultaneously with the indentation of the annular member.

The manifold tube may be provided with one or more holes or slots in the wall of the tube opposite each passage member, or it may be provided with a continuous slot throughout the greater part of its length.

Alternatively, the manifold tube may be formed with integral longitudinally extending fins projecting from its inner wall and portions of the tube wall are removed at the spacings for the passage members in order to leave gaps in the wall which are bridged by the fins.

In order to assist in the location of the passage members relative to the manifold tubes, the passage members may be provided with internal stiffening members, and these stiffening members are arranged to extend beyond the passage members and through apertures provided in the manifold tubes thereby locating the passage members with respect to the manifold tubes.

As previously mentioned, the various components of the heat exchanger may be advantageously bonded together by means of an adhesive, but alternatively the component parts may be bonded together by other means such as electron beam or laser beam welding, plasma art welding or vacuum brazing.

Preferably the passage members are made from a metal foil, that is to say sheet material having a thickness up to approximately 0.012. The metal foil is preferably an aluminum foil and it will be understood that the term aluminum includes alloys of aluminum. The manifold tubes and surrounding members may also be made of metal e.g. aluminum. Alternatively the manifold tubes and/or the surrounding members may be made of a synthetic plastics material, for example by moulding and extrusion techniques, in which case the apertures through the manifold tubes may be formed during the moulding operation.

Preferably, the manifold tubes and surrounding members are of circular cross-section, but they could also be of any other convenient cross-section, e.g. rectangular.

According to another aspect of the invention, a heat exchanger comprising at least one manifold interconnecting a plurality of passage members through which a liquid can flow is provided with an expansion container supported from the heat exchanger and connected to the manifold for receiving liquid overflowing from the heat exchanger due to expansion, and allowing such overflow liquid to be syphoned back into the heat exchanger, as required.

According to a feature of this aspect of the invention, a bottle-like container is connected to one end of a manifold of the heat exchange structure and a non-return valve is provided between the interior of the container and the manifold, said valve opening to allow liquid to overflow into the container when the liquid in the heat exchanger reaches a predetermined pressure. The structure also includes a syphon tube and further non-return valve which allows liquid in the container to syphon back into the heat exchanger when the pressure therein drops. Preferably, a filler cap to the heat exchange structure is also located at one end of the manifold assembly above the said container.

According to one embodiment, the two non-return valves may form part of a composite valve structure and employ a common seating member for the two valves.

The valve structure may be so designed that air coming out of solution from the liquid in the heat exchanger and collecting in the region below the filler cap is exhausted into the container when the non-return valve opens to receive liquid from the heat exchanger.

The invention will now be further described by way of example with reference to the accompanying drawings, in which:

FIGS. 1A, B and C respectively show three alternative 3 methods of securing passage members to a manifold tube to form a radiator core,

FIG. 2 is a cross-section through the manifold tube of FIG. 1,

FIG. 3 is a cross-section through an alternative form of manifold tube,

FIGS. 4 and 5 are respectively a longitudinal section and a cross-section through a further form of manifold tube,

FIGS. 6 and 7 are respectively a longitudinal section and a cross-section illustrating a means of locating the passage members with respect to a manifold tube;

FIG. 8 is a perspective view, partly cut away, of a portion of one embodiment of manifold type radiator according to this invention.

FIG. 9 is a side-elevational view, partly in section, of a portion of a further embodiment of radiator construction according to this invention, including an expansion container,

FIG. 10 is a fragmentary view of another embodiment showing a modified valve arrangement for the expansion container, and

FIG. 11 is a fragmentary view of yet another embodiment, showing a further valve arrangement for the expansion container.

The radiator cores to be described generally comprise a pair of spaced manifold tubes 1 interconnected by a plurality of tubular passage members 2 arranged side-byside. Each passage member is formed from a pair of strip elements 2a of aluminium foil having a thickness of up to approximately 0.012", for example of about 0.005". Each element is formed for example by pressing the strip to define a central channel provided with flanges 2b along its side edges. Adjacent the opposite ends of each passage member, each side wall is provided with a circular aperture through which pass the manifold tubes 1, formed with apertures 1a located opposite each passage member. Thus the manifold tubes form ducts by means of which liquid may be fed to and removed from the passage members. The liquid is supplied from a header tank or the like which may be spaced from the radiator structure.

Located in the space between adjacent passage members are a series of cooling fins 2 0 which are bonded to the walls of the passage members and form heat exchange surfaces for dissipating the heat extracted from the liquid flowing through the heat exchange structure.

FIGS. 1A, B and C show a sectional view of part of a radiator core in the region of a manifold with three alternative methods of attaching the manifold tube 1 to the passage members 2. In FIG. 1A, the passage member 2 is attached to the manifold tube 1 by flanged ferrules 3 which are slid over the manifold tube and bonded to the manifold tube and to the passage members. Any of the hereinbefore mentioned bonding means can be used. The passage members can have their width in the region of the manifold increased by forming a local bulge or plateau, as illustrated at 4 and this bulge or plateau can have an external lip (not shown) to further improve the bonding and location of the ferrule 3.

An alternative to the use of the ferrules 3 is shown in FIG. 1B. In this construction a single distance piece 5 is used to span the space between adjacent passage members. The methods of bonding the distance piece to the manifold tube and passage members can again be as hereinbefore described. However, where an adhesive is used for bonding, a small hole or holes 6 is/ are preferably formed in the centre of each distance piece 5. In addition an annular recess 7 may be formed on the inner cylindrical wall of the distance piece or alternatively on the outer wall of the manifold tube. When the distance piece 5 is in its correct position on the manifold tube 1, the nozzle of an adhesive dispensing machine is applied to the hole(s) 6 and adhesive is injected into the hole and into the recess 7, to bond the ferrule to the manifold tube. The

end flanges 5a on the distance piece are bonded to the adjacent walls of the passage members 2.

In FIG. 1C a distance piece 8 is positioned over the manifold tube 1 and is mechanically secured thereto by deforming the outer wall of the distance piece. The depression 9 so formed causes a distortion on the inner wall and material flows into a corresponding depression 10 on the manifold tube. This latter depression may be preformed or may be formed by the single operation of applying a deforming tool to the distance piece after the distance piece has been correctly positioned over the manifold tube. The depressions 10 formed in the distance piece can be of any convenient shape and may, for example, take the form of one or more concave areas disposed radially round the distance piece, or they can be in the form of a single annular groove. In this embodiment it is only necessary to apply adhesive or other bonding means to the flanged end faces 8a of the distance piece 8.

FIG. 2 shows a cross-section of the manifold tube 1 in the region of a passage members and illustrates one method of forming the apertures 1a by drilling an array of holes disposed radially round the manifold tube.

An alternative method of forming the apertures in the manifold tube is shown in FIG. 3, in which a milling cutter is used to form slots 1b in the manifold tube.

A further embodiment of the manifold tube is shown in FIGS. 4 and 5. In this embodiment, the tube 1 is extruded with integral fins 11 formed on its inner wall. Prior to its assembly with the passage members, the manifold tube is placed in a lathe and grooves 12 of width S are formed by a plunge turning tool 13. This tool is fed into the manifold tube until it has machined away all the wall, down to the diameter D (FIG. 5) leaving only the fins 11 to act as ties across the gap 12. It should be noted that diameter D must always be slightly less than the inner diameter of the tube.

If desired, the tool 13 can also be incorporated with an auxiliary tool 14 to form the small annular grooves 10 which co-operate with the distance piece 8, as previously described in connection with FIG. 1C.

During the assembly of the radiator structure it is necessary to ensure that the passage members 2 are correctly positioned on the manifold tube 1 so that the apertures in the manifold tube, line up with the passage members. This may be achieved by the use of suitable jlgS.

If distance pieces such as 5 and 8 are used, it is not desirable that the position of the passage members should be determined by fixing a close tolerance on the width of the passage members and distance pieces, since cumulative errors would soon cause a considerable loss of accuracy as the core is built up.

In the embodiment employing distance pieces 8 which are mechanically located on the manifold tube, the position can be determined by using a jig which holds the distance piece and the deforming tool relative to another, e.g. the next-but-one, series of apertures on that part of the manifold tube which is still exposed. The jig moves up one series of apertures at a time as the core is built up.

An alternative arrangement for positioning the passage members on the manifold tube which is applicable to either the mechanically locked or bonded distance pieces, or the single ferrules construction is illustrated in FIG. 6 and FIG. 7 In this embodiment, the passage members 2 are provided with stiffening members 15, which extend beyond the passage members and are a sliding fit in the aperture 1b of the manifold tube 1 and passes through these apertures.

In the foregoing description of the various embodiments the manifold tubes and distance pieces or ferrules may be made in metal, and the various cross passages etc. formed by machining. It is however possible that both the manifold tubes and the ferrules or distance pieces could be made of a moulded or extruded plastics material, and, in the case of a moulded material, some or all of the apertures can be incorporated in the mould.

FIG. 8 is a perspective view partly cut away of part of a radiator core embodying the features of FIG. 1B, FIGS. 4 and 5, and FIGS. 6 and 7.

One end of each manifold tubes is provided with a connection to receive a hose for supplying or withdrawing water from the radiator core. The other ends of the manifold tubes are sealed by caps (not shown). The present invention thus provides a manifold type heat exchanger of bonded construction in which the manifold tubes are continuous across the width (or depth) of the core structure and takes the tension forces produced by internal fluid pressure within the passage members.

It will be understood that a heat exchanger according to this invention may only be provided with a manifold tube interconnecting one end of the passage members, the other end of the passage members communicating directly with a tank or the like.

Referring now to FIG. 9 the radiator core shown again generally comprises a pair of spaced manifold tubes 1 interconnected by a plurality of tubular passage members 2 arranged side-by-side. In this embodiment, each manifold tube 1 is provided with a continuous slot 10 extending substantially throughout its length in order to provide communication with the passage members 2. The spacing between the passage members is defined by the flanged distance pieces 5 which are bonded to the manifold tube 1. The flanges 5a on the distance pieces are bonded to the passage members 2. The space between adjacent passage members contains a series of cooling fins which are bonded to the walls of the passage members and form heat exchange surfaces for dissipating the heat extracted from the liquid flowing through the heat exchange structure.

The filler cap for the radiator structure is provided at the upper end of a tubular member 26 attached to one end of the upper manifold tube 1, the lower end of this member 26 carrying an expansion container 27 in the form of a bottle e.g. of a plastics material. A valve structure, generally indicated at 28, is located Within the lower end of member 26 between the manifold tube and the bottle 27. This valve structure comprises a pressure nonreturn valve consisting of an annular seating surface 29 engaged by the outer part 3011 of the annular valve seating 30 urged by the spring 21; which opens when a pressure is generated in the radiator core to allow water to overflow into the container down the syphon tube 22. When the pressure in the radiator core drops sufficiently, the further non-return valve, comprising valve member 23, the spring 24 and inner portion 30b of the seating 30, opens to allow water to be syphoned back up the syphon tube 22 into the radiator.

During operation of the radiator, air coming out of solution may collect in the region below the filler cap 25 and it is essential that this be exhausted into the container 27 when the pressure valve opens, otherwise the air pocket may extend into the manifold tube and cause aeration in the passage members with consequent loss of heat transfer and possible damage to the radiator. This may be avoided by making the entry point to the pressure valve above the level of the manifold tube, as

shown in FIG. 10, wherein the inlet tube 31 to the pressure valve is carried up to the underside of the filler cap 25.

FIG. 11, shows a further embodiment wherein the upper manifold tube is extended at 32 to provide a seating 33 for a pressure valve 34 carried by the filler cap 25. Thus, when a suflicient pressure is generated in the radiator the valve 34 opens and allows liquid to overflow into the container 33 at the same time exhausting any air collected in the region below the filler cap. The lower part of the extrusion also carries the further non-return valve 35 communicating with the syphon tube 22 in the container 27 and which opens to allow liquid in the container to syphon back into the radiator.

In all of the embodiments an aperture 27a is provided to vent the container 27 to atmosphere.

Instead of using a separate bottle-like container 27, the container could form part of the radiator structure. For example, a side plate of the radiator could be of hollow, e.g. rectangular, section and sealed at the ends to form the container. Moreover the tubular member 26 could be a die-casting or stamping of rectangular shape, having a cylindrical seating for the cap 25.

We claim:

1. A heat exchanger, including a plurality of passage members through which a liquid can flow, the passage members having walls provided with apertures; a manifold tube passing through the apertures in the walls; and a collar surrounding the manifold tube between each pair of opposing walls of adjacent passage members, wherein the improvement comprises:

(a) the walls being of light metal material up to .012

inch thick;

(b) the manifold tube having an aperture extending opposite at least two of said passage members to allow for liquid flow between the manifold tube and those passage members;

(0) the collar being bonded and sealed by an adhesive at both its ends to said opposing passage member walls; and

(d) the collar being bonded by an adhesive to the external surface of said manifold tube.

2. A heat exchanger, as in claim 1, wherein said light metal is aluminium.

3. A heat exchanger, as in claim 1, wherein each said collar is of aluminium.

4. A heat exchanger, as in claim 1, wherein each said collar is of synthetic plastic.

References Cited UNITED STATES PATENTS 3,104,701 9/1963 Jacoby, Jr. -175X 3,396,785 8/1968 Kirsch 165-175 FOREIGN PATENTS 193,607 3/19'23 Great Britain 165-130 ALBERT W. DAVIS, JR., Primary Examiner US. Cl. X.R. 

